Mitsui O.S.K. Line announced Monday that it has completed measures to reinforce the hulls of three of MOL Comfort’s sister vessels after having conducted an investigation into the causes of the mid-June 2013 hull fracture of the MOL-operated containership in the Indian Ocean.

MOL began preventative measures to enhance the safety of all six sister vessels immediately following the incident, which left the fore and aft section of the 2008-built MOL Comfort adrift for weeks before both would eventually catch fire and sink.

MOL says that measures taken to reinforce the hulls of MOL Celebration, MOL Courage, and MOL Creation were recently completed, and that these vessels returned to Asia-North Europe service beginning August 10.

The work done on the three containerships was aimed at strengthening the hull structures to approximately twice that required by Nippon Kaiji Kyokai (ClassNK), Japan’s classification society, which conforms to the safety standards of the International Association of Classification Societies (IACS).

ClassNK has confirmed that the work done on these three vessels was executed according to plan. In addition, Lloyd’s Register, which MOL appointed as a technical consultant, has expressed its opinion that the structural reinforcement completed for the vessels is considered to be the best preventive measure against a similar failure at present, MOL says.

Meanwhile, MOL Charisma and MOL Competence are among the three remaining sister vessels that are already at the Mitsubishi Heavy Industries dockyards and their hull reinforcement will be completed by the end of September to beginning of October. The work for MOL Commitment which was newly delivered this June is expected to be completed by February 2014, MOL says.

We have reached out to MOL directly for further comment on what specific modifications were made.